[U-Boot] [PATCH v2] gpio: add gpio-hog support

[Michal Simek]

Hi,

On 27. 05. 19 14:06, Heiko Schocher wrote:
> Hello Michal,
> 
> Am 27.05.2019 um 13:34 schrieb Michal Simek:
>> On 27. 05. 19 12:49, Heiko Schocher wrote:
>>> add gpio-hog support. GPIO hogging is a mechanism
>>> providing automatic GPIO request and configuration
>>> as part of the gpio-controller's driver probe function.
>>>
>>> for more infos see:
>>> doc/device-tree-bindings/gpio/gpio.txt
>>>
>>> Signed-off-by: Heiko Schocher <hs at denx.de>
>>>
>>> ---
>>> not yet started clean travis build, see result:
>>> https://travis-ci.org/hsdenx/u-boot-test/builds/537732421
>>>
>>> Changes in v2:
>>> - move gpio_hog() call from post_probe() to post_bind()
>>>    call. Check if current gpio device has gpio-hog
>>>    definitions, if so, probe it.
>>
>> I am using i2c to gpio chip and with v2 this chip is not listed via dm
>> completely. It means something is wrong for sure.
> 
> What do you mean with "this chip is not listed via dm completely" ?

first of all I am using zcu102
http://git.denx.de/?p=u-boot.git;a=blob;f=arch/arm/dts/zynqmp-zcu102-revA.dts;h=6e22871713139517ad5f7f1d2e659690233bd946;hb=HEAD#l129

There are 2 i2c-gpio chips  @20 and @21. @20 has hogs and it is not
listed via dm tree when v2 is applied (v1 is without any issue).
@21 is seen there.

> 
>> It looks like that parent is not probed that's why it is failing.
> 
> I use this on the aristainetos board, work currently on rework for DM/DT
> usage in U-Boot, dts not yet in u-boot but in linux, see:
> 
> https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/arch/arm/boot/dts/imx6qdl-aristainetos2.dtsi#n286
> 
> 
> and added for u-boot now gpio hog definitons:
> 
> &i2c3 {
>         pinctrl-names = "default";
>         pinctrl-0 = <&pinctrl_i2c3>;
>         status = "okay";
> 
>         expander: tca6416 at 20 {
>                 compatible = "ti,tca6416";
>                 reg = <0x20>;
>                 #gpio-cells = <2>;
>                 gpio-controller;
> 
>                 env_reset {
>                         gpio-hog;
>                         input;
>                         gpios = <6 GPIO_ACTIVE_LOW>;
>                 };
>                 boot_rescue {
>                         gpio-hog;
>                         input;
>                         gpios = <7 GPIO_ACTIVE_LOW>;

nit: there could be also line-name setup.

>                 };
>         };
> };

The setup looks the same as I have here.

> 
> works fine for me ...
> 
> => dm tree
>  Class     Index  Probed  Driver                Name
> -----------------------------------------------------------
>  root         0  [ + ]   root_driver           root_driver
> [...]
>  i2c          2  [ + ]   i2c_mxc               |   |   |-- i2c at 21a8000
>  gpio         7  [ + ]   pca953x               |   |   |   |-- tca6416 at 20
> 
> => gpio status
> [...]
> Bank gpio at 20_:
> gpio at 20_6: input: 0 [x] env_reset.gpio-hog
> gpio at 20_7: input: 1 [x] boot_rescue.gpio-hog
> =>
> 
> Hmm.. how can I reproduce your problem?

Take a look but IIRC you should have zcu102 around too.

Thanks,
Michal